As enjoyable as Countryside Community Theatre's The Wizard of Oz is, the most thrilling part is this: The witches fly. While L. Frank Baum's familiar story of the Kansas girl who's blown to the land of Oz by a tornado has its fill of magic, Countryside adds some magic of its own by making its witches (and a flying monkey) airborne. It's a special touch to a show that, during Friday's opening-night performance, proved to be a gratifying evening's diversion - if a long one, running three hours from beginning to end.